1. Field
This invention concerns a joint with adjustable angular range for braces, which can be applied as an aid for joints of the human body such as the knee, the ankle, the elbow or similar.
More specifically, this invention refers to a joint for instability control, in particular of the knee, the ankle, the hip or the elbow but in theory for any joint. The joint is therefore part of a knee brace or other similar brace that can be used during sports activities or also during rehabilitation and/or post-operatively.
The joint according to the invention is also used to achieve control of translation, hypertension and rotation of the joint and is equipped with a system of limit stop adjustment to control the angular range both in extension and flexion, in other words it is equipped with a new system of R.O.M. (Range Of Motion) adjustment.
This invention can be applied in the orthopedics industry with particular reference to manufacturers of prostheses and braces.
2. Background Art
It is known that subjects with orthopedic problems of the knee, ankle or elbow joints, above all as the result of a previous surgical operation, need to use an orthopedic brace designed to guarantee the function of a hinged constraint between the femur and the tibia or other joint lever points, supporting stress that would otherwise be harmful for the joint.
It is in fact known that the function of a brace is, in general, to guarantee the relative immobilisation, or limitation, of a joint affected, for example, by trauma, arthrosis, sprained ligaments or which have undergone surgery.
Another use of braces is functional rehabilitation or re-education, where the brace can be used to reduce the load on a joint and lessen the pain, or used for preventive purposes in cases of osteoporosis or bone fragility.
Knee braces usually consist of a rigid and enclosing frame designed to guarantee adequate harnessing of the joint and prevent the onset of strain on the ligaments and synovial membranes when the injured and/or convalescent subject is walking.
According to background art, in the specific case of the knee, the frame of the knee brace comprises means of constraint for the femur and the tibia in areas close to the knee and a structure connecting these means with a jointed hinge positioned at the level of the knee. The means of constraint usually consist of half-rings encircling both the femur and the tibia of the injured subject.
The frame of the knee brace comprises uprights, positioned laterally with respect to the femur and the tibia, connected by respective joints generally equipped with 4 pivots designed to ensure excellent mobility achieved by the presence of multiple centres of rotation.
To ensure adequate freedom of movement of the joint, the frame develops almost exclusively at the sides of the knee in order to allow the correct reciprocal oscillation between the femur and the tibia.
Joints with four pivots are used to ensure the hinged connection of the portions of frame fixed to the femur and to the tibia and they extend during of the joint and shorten when the joint is extended.
This considerably reduces the risk of relative movements of the knee brace and of it slipping downwards.
It is also known that, depending on the severity of the injury, each subject needs different levels of angular range freedom, and braces have thus been produced that comprise means for the adjustable limitation of angular range.
Traditional joints for knee braces with adjustable angular range generally comprise a platform equipped with at least one pair of hinge couplings for the respective uprights, equipped with means for restraining the joint in question, in which said platform comprises a central shaped plate and at least one housing for an extractable insert which abuts against the plate and at least one end of an upright.
The joint comprises means of temporary restraint for the inserts with the purpose of limiting the movement of the joint in extension and/or flexion; in order to be able to adjust the R.O.M. in the various possible angular configurations, the flexion and extension limiting insert must be interchangeable with inserts having different profiles.
The shape of the inserts is such as to limit the reciprocal angular range between the uprights constrained to the joint, the shape differing in order to obtain different angular ranges according to the insert used.
According to the known solutions, the joint presents internal housings for the inserts, consisting of accessible slots formed inside the platform. At the level of each slot, the base surface of the platform presents an opening designed to make the housing of the respective insert visible.
While these solutions solve the problems concerning the R.O.M. (Range of Motion) adjustment system of orthopedic braces with angular range, they show other problems which will be described below.
First of all, the traditional insert system makes use of components of a certain size, creating a first difficulty in the use of the brace due to the considerable thickness of each hinge. The adjustment system is also difficult to use as regards the limited stability of the inserts and it is also difficult to change the inserts when it is necessary to vary the range.
In addition, also according to known solutions, the replacement of the wedge inserts involves the use of specific tools such, for example, screwdrivers to remove the screws and other components fixed on the joint, thus further complicating the replacement steps.
Document WO-A-2004/078078 discloses a joint with adjustable angular range for a knee brace comprising two rods, two plates connected to each other by rivets which represent four joint points, and two wedges insertable between the plates. The wedges are inserted and extracted by means of a specific tool such as a screwdriver.